Latch mechanism for dump trucks



De -30, 1947. R A. PENNEY 5 LATCH MECHANISM FOR DUMP TRUCKS Original Filed Dc. 26, 1944 2 Sheets-Sheet i lam/Mom) A. PE'NNE'F Dec. 30, 1947. R. A. PENNEY LATCH MECHANISM FOR DI IMP TRUCKS Original Filed Dec. 26, 1944 2 Sheets-Sheet 2 RAYMOND A. PENmE-Y Reissued Dec. 30, J94? LATCH MECHANISM FOR DUMP TRUCKS Raymond A. Penney, Minneapolis, Minn., as-

signor, by mesne assignments, to Gar Wood Industries, Inc., Detroit, Mich., a corporation of Michigan Original No. 2,401,660, dated June 4, 1946, Serial No. 569,753, December 26, 1944.

Application for reissue March 6, 1947, Serial No. 732,870

Claims. (Cl. 29838) This invention relates to power operated dump truck bodies, and the primary object is to provide means for locking or latching the body in its horizontal or load carrying position, power actuated means for tilting the body to dump its load, and a single control member for operating the looking or latching means and the power actuated means, whereby the body may be secured in its normal horizontal position against accidental tilting and whereby the power actuated means cannot be operated unless and until the securing means has first been released.

In dump trucks of this general type it has been found that there is frequently a tendency for the dump bodies to tilt upwardly at their forward ends during transport and this is particularly noticeable where the trucks may be used for transporting cattle or any other type of load which may shift back and forth, and the tendency is particularly noticeable as the truck travels over an inclined road surface. While this tilting tendency may not result in the body actually or fully raising its forward end it does cause wear upon the hoist. the hinge, and other parts of the truck. It is therefore an important object of my invention to provide a lock or latch mechanism by which the forward end of a dump body may be held down solidly at all times other than when the hydraulic hoist is operated to tilt the body toward dumping position. Another object is to provide a latch mechanism for this purpose which may be-readily applied to the truck and when properly adjusted at the outset will opcrate entirely automatically under the control of the usual hand lever used for operating the hoist. These and other more detailed and specific objects will be disclosed in the course of the following specification, reference being had to the accompanying drawings, in which- Fig. 1 is a side elevation of a dump truck with parts thereof broken away and in section, showing, my improved control mechanism applied thereto and with the dump body partially raised, the latch being in its released position.

Fig. 2 is an enlarged fragmentary vertical section through a forward part of the body and the associated frames, and showing my latch mechanism in its locked or operative position.

Fig. 3 is a fragmentary vertical section along the line 3-3 in Fig. 2, with latch actuating parts omitted for the sake of clarity.

Fig. 4 is a horizontal section along the line 4-4 in Fig. 2.

Fig, 5 is a fragmentary vertical section along 2 the line 5--5 in Fig. 2, but with all frame parts omitted.

Referring now more particularly and by reference characters to the drawings, A designates generally a dump truck of conventional form upon which is mounted a dump body B which is raised and lowered by a conventional hoist mechanism C. The truck A has the usual chassis ll) upon which is mounted a chassis frame or sub-frame I comprising side channels l2, secured by brackets |3 to said frame l0, and joined at their front and rear ends by cross bars l4 and I5, respectively. The dump body B has a body frame or sub-frame 16 which comprises longitudinal beams rigidly connected by cross beams l8 upon which the body is mounted. Adjacent its rear end and some distance therefrom the body frame l6 carries side brackets I9 which are pivotally mounted upon a. cross shaft 20 supported at the rear end of the frame II. This connection is so made that the body B may tilt upwardly and rearwardly at its forward end about a transverse pivot axis, and the body normally rests horizontally upon the frame I during transport, but may obviously be moved to a rearwardly sloping position at which the contents may be dumped from the rear end.

This dumping movement of the body is carried out by the hoist mechanism C and this ordinarily comprises at least one cylinder 2| the forward end of which is pivotally supported and mounted at 22 between the channels l2 of the sub-frame I so that the cylinder is braced against forward movement but is permitted to swing in a vertical plane at its rear end. A plunger 23 projects from the rear end of the cylinder 2| and it is pivotally attached at 24 to the body frame l6 forwardly of and above the pivot 20. The arrangement is thus such that the admission of fluid under pressure to the cylinder 2| will cause the plunger 23 to move rearwardly exerting a lifting and rearwardly pushing force upon the body causing it to move toward its dumping position. On the other hand, the plunger 23 may be allowed to move inwardly into the cylinder 2|, while fluid is permitted to escape therefrom, so that the body B will return of its own weight toward normal, transport position.

The fluid is permitted to enter the cylinder 2| or to escape therefrom under control of a valve mechanism 25 which is operated by a valve rod 26 connected at its forward end to an arm 21. The valve mechanism 25 is carried at the forward end of the cylinder 2|, and the arm 21 forms a part .of a relay, indicated generally at 28, including a cross shaft 29 whichis .iournaled at the rear ends of supporting bars and 3|, welded or otherwise suitably secured to the front cross bar |'4 of the sub-frame The arm 21 is attached to one end of the cross shaft 29 and projects upwardly therefrom while another arm 32 is secured to the opposite end of the shaft 29 and depends therefrom. An operating rod 33 is pivotally connected to the lower end of the arm 32 and extends forwardly therefrom into or beneath the cab 34 of the truck A whereat it is connected to an op.- erating lever (not shown) convenient to the hand of the driver of the truck. This valve operating mechanism is wholly conventional and the ar-. rangement is such that the oscillation of the shaft 29 will move the upper end of the arm 21 forwardly and rearwardly and'position thevalve 25 to admit fluid to the cylinder 2|, to hold fluid therein, or to allow the fluid to escapees may be required for proper positioning of the dump body B. The arrangement is further such that fluid is admitted to the cylinder 2| to raise or tilt the body B in response to a rearward movement of the arm 2'! and of the valve rod 26.

My present invention includes a latch mechanism, designated generally at D, by which the forward end of the dump body B is locked in its down or transport position; Said mechanism D comprises a latch 35 having a hook or nose portion 33 adapted to engage the horizontal bight portion 31 of a U-shaped yoke or keeper member 38. The spaced upright legs 39 of this member 38 are secured, in any suitable manner, such, as by welds 45, to a cross member 4| attached atop the beam [1 in an appropriate position and in such manner that the keeper member 38 depends from the body and is rigid with respect thereto. The lower end portion of the latch 35 is pivotally attached to a bracket or mounting member 42 which is bifurcated to provide transversely spaced cars 43 apertured at 44 to receive a pin 45 by which said pivotal connection is made. The bracket member 44 has an integral depending and threaded stem or stud 46 and the front frame bar M of the chassis subframe H is apertured, as indicated at 41, to pass this stem 46. A nut 48 and lock washer 49 are provided on the lower end of the stem 46 and when screwed upwardly the nut obviously will rigidly clamp the bracket 42 to said bar M. A centering washer 50 is provided beneath the bracket 42 and above the bar M, as clearly indicated.

The latch 35 is thus so mounted that it may swing at its upper end in a longitudinal upright plane and is so positioned that its hook or nose portion 36 may overhang the bight portion 31 of the keeper member 38 to thus securely lock the forward end of the body against upward movement relative to the truck and the frame thereon. The latch 35 is normally urged in th forward direction by a torsional coil spring 5| the ends of which are hooked, as indicated at 52 and 53, around rear edges of the latch and one of the ears 43, respectively. Said spring 5| is positioned around a hub 54 formed at one side of the latch adjacent its lower end and adjacent and above. which the latch is offset laterally, as indicated at 55. The upper portion of the latch 35 is thus centered with respect to the keeper member 38 while its lower portion is offset to one side thereof, as clearly indicated at Fig. 3. The lower forward portion of the latch 35 then has a;finger portion 55 which is positioned forwardly of the base portion 57 of the bracket 42 and which base portion joins the lower portions of the cars 43 This base portion 5'! is provided with a tapped bore 58 extending from front to rear thereof and in this bore is screwed a set screw 59 the forward end of which is adapted to engage and limit rearward movement of the finger portion 56 of the latch. Thus the forward movement of the latch 35 at its upper end, responsive-to the spring 5|, may be properly positioned with respect to the keeper member 38. When once made, this adjustment is locked by the lock nut Ell and thereafter the l'atch35 may swing only in a rearward direction from its perative position, as indicated in Fig.

The lower extremity of the finger portion 56 of the latch islaterally offset in a direction opposite to the offset 55 as indicated at 6|, in order to bring it directly into alignment with the forward end of the set screw-59.

The latch35' is automatically operated responsive to. the movement of the valve rod 26 by means of an actuating rod 52 having its forward end pivotally attached, as indicated at 63, to the upper end of the latch. The, actuating rod 62 extends. from the latch the rearward direction substantially parallel to the valve rod 28 and pro.- iects. slidably thro sl-iv an. op nin 6. d. in the endof a tie, link 65 constituting a lost motion, connec on which. conn cts the o d i link. 651s rigi y secured by nuts 66 an k washe s 6.1 t th v lve operati rod 2.6 and from this point the. link, trave ses th pa e. he: we n h rods, as. c early ind cated. in Fig. 4., The rear portion of. the a tuating ro 62 is thr aded to receive a ha of. n 68 nd a loo Washer 61 which are positioned rearwardly-ofthe, nd. of the. link 55. w ere n the op nin 64. i ocated. The arrangement is obviously such that the rearward movement of the valve rod 26. and onsequent. rearwa d. mov ment of; the li k. will ausethe l er t butt a a nst the. nu 68 and. br n about a corr spo d ng re r movement. o the actuating rod 5,2. Such movement will obvio sl swing the upper end of the latch. 35 in. a rearward direction.

The upper forward portion of the latch 35 has I af wa dly nd downwardly s op g c m rface Ill terminating at the'hook or nose portion 36 and gainst which the keeper member 30. m y r de to swine the latch 35. back as required to bring the bi ht portionfl beneath the hook .6.

While he peration of the mech ni m is p h ably understood from the foregoing it will be briefly described as follows:

As he init al ins al a ion. an diustments are. madethe link 651s. so posi ioned upon th valve rod 25 and the nut 58. is o l edon e actuat n rod 62 thatin the normal or h l in pos ti n o the valve 25 the end o th link 65 will lust lie rearward. contact wi h. the .for-wardmos n -68.. In making such. ad u tment the t ew 59 also adjusted as required to bring the nose portion or hook 36 of the. latch 35 properly over the bight portiQn 31 of the keepermember 38,. Once these adjustments are made and. locked they may be, forgotten and thereafter as the controls are operated toadmitfluid to'the cylinder 2| the rearward movement of the valve rod 26 in opening the valve will at the very outset move the actuating rod 62 rearwardly or release the latch 35 from the keeper member 38. Thus by the time that fiuidaction in the cylinder causes the body B to startits upward movement the latch is entirely released so that no jammingor breakage of parts. may occur. So long as the valve 25 remains open for admitting fluid to the cylinder 2| the latch 35 remain in a rearwardlyswung inoperative position, as shown inFig; 1,.but immediately as the valve 25 is moved to its normalholding positionv the forward movementzof the rod. 26 will llow' the latch to swing back forwardly under the. influence of the spring :51 until it returns to the normal position of Fig. 2. As the body B is now tilted forwardly by movement of thevalve m '2. position for exhausting fluid from the cylinder the: forward movement of the rod'zli' will cause the link 65 to merely slide forwardly along the rod 52 with a lost motion action so. that it has no effect upon the position-of the latch. Then as the body approaches its down or transport position the keeper member 38 will cam over the surface 10 of the latch, forcing-it rearwardly until the bight portion 31 is below the level of the hook '38 upon which the spring will return the latch to its locked position so that it will hold down the body. It will be apparent from the foregoing that the operation is thus completely and entirely automatic and that the latch can inno circumstances interfere with the normal operation of the dump truck.

In some installations the valve rod 26 may lie to the opposite side of the center of the truck to that shown in Fig. 4 but the application of the latch mechanism may be made in such cas with equal facility merely by reversing the lateral direction in which the link 55 extends. The link may further be twisted slightly at its end, as indicated at H in Fig. 4, in order to compensate for any differences in the relative angle of the valve rod 26 and actuating rod 62, as shown in Figs. 1, 2 and 4.

It is understood that suitable modifications may be made in the structure as disclosed, provided such modifications come within the spirit and scope of the appended claims.

Having now therefore fully illustrated and described my invention, what I claim to be new and desire to protect by Letters Patent is:

1. In a dump truck having a body, a hoist unit operative to move the body upwardly and downwardly at one end and a hoist control member movable in one direction for raising the body and in an opposite direction for lowering the body, a latch mechanism normally locking the body against upward movement, and means responsive to movement of the said control member in the first mentioned direction for releasing said latch mechanism, said means including a lost motion device whereby opposite movement of said control member will have no effect on the latch mechanism.

2. In a dump truck having a dump body and hoist mechanism for raising and lowering one end of the body, said mechanism including a hoist control valve rod movable in one direction for raising the body and movable in an opposite direction for lowering it, a latch normally operative to lock the body against upward movement, an actuating rod for the latch and means connecting said actuating rod to the valve rod in such manner that movement of the latter in a direction for initiating upward movement of the body will move said latch to an inoperative position, while movement of the Valve rod in the opposite direction will have no effect on the actuating rod.

3. In a dump truck having a dump body and hoist mechanism for raising and lowering one end of the body, said mechanism including a hoist control valve rod movable in one direction for raising the body and movable in an opposite direction for lowering it, a latch normally operative to lock the'body against upward movement,

on actuating rod for the latch, a link connected;

between the valve and actuating rods, said means onthe actuating rod for cooperation with,

the linkmember whereby movement of the valve rodfor raising the body will move said, actuating rod to release the latch.

5. In a dump truck having asdump body and hoist mechanism for raising: and lowering one.

end of the body, said mechanism including a hoist control valve rod movable in one direction for raising the body and movable in an opposite direction for lowering it, a latch normally operative to lock the body against upward movement, an actuating rod for the latch, a link member extending between the valve and actuating rods and movable as a unit with the valve rod, and said link having a lost motion connection with the actuating rod whereby movement of the valve rod in one direction only will operate the actuating rod to move said latch to an inoperative position.

6. In a dump truck having a dump body and hoist mechanism for raising and lowering one end of the body, said mechanism including a hoist control valve rodmovable in one direction for raising the body and movable in an opposite direction for lowering it, a latch normally operative to lock the body against upward movement, an actuating rod for the latch, a link member adjustably connected to the valve rod, and stop means adjustable along the actuating rod for engagement by the link member whereby movement of the valve rod in a direction for initiating upward movement of the body will move said latch to a position for releasing the body.

7. In a dump truck having a dump body movable upwardly and downwardly at its forward end and a hoist mechanism for operating the body and said mechanism including a valve rod movable rearwardly to cause the body to rise, a latch mechanism for normally locking the forward end of the body against upward movement,

said latch mechanism including a latch swingable rearwardly to release the body, an actuating rod connected to the latch and extending alongside the said valve rod, a link member secured at one end to the valve rod and having an aperture in its other end slidably fitting the actuating rod, and stop means on the actuating rod rearwardly of the link member.

8. In a dump truck having a dump body movable upwardly and downwardly at its forward end and a hoist mechanism for operating the body and said mechanism including a valve rod movable rearwardly to cause the body to rise, a latch mechanism for normally locking the forward end of the body against upward movement, said latch mechanism including a latch swingable rearwardly to release the body, an actuating rod connected to the latch and extending alongside the said valve rod, a link member secured at one end' to the valve rod and having an aperture in its other end and slidably fitting the actuating rod, and stop means adjustable forwardly and rearwardly along the actuating rod. and positioned rearwardly of the link member whereby rearward movement of the valve rod will draw the latch rearwardly to free the dump body.

9. In a dump truck having a frame and a body supported for upward and downward movements at its forward end with respect to said frame, a U-shaped keeper secured tothe body, a bracket member secured to the frame, a latch pivotally mounted at its lower end'on'said bracket memher and having a hook at its upper end for forwardly and downwardly engaging the keeper member responsive to forward swinging movement of the latch, the lower end of the latch having a depending finger portion, and a set screw carried by the bracket member for rearwardly engaging said finger portion and for limiting forward keeper engaging movement of the latch.

10. In a dump truck having a tiltable body, means for releasably securing the body in normal horizontal position, hydraulic means i'or tilting the body including a control valve, and a. manually operated device connected with said body securing means and said valve to release the securing means and open the valve to operate the hydraulic means, said device having a lost motion connection with respect to said body securing means, whereby it will actuate the latter inone directional movement of the manually operated device but not in another directional movement thereof.

RAYMOND A. PENNEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 

